What's more, the Times adds, nearly 2,000 gamma radiation-induced mutant crop varieties have been registered around the world, including Calrose 76, a dwarf varietal that accounts for about half the rice grown in California, and the popular Star Ruby and Rio Red grapefruits, whose deep colour is a mutation produced through radiation breeding in the 1970s. Similarly, Johnson tells Pruned that "most of the global production of mint oil," with an annual market value estimated at $930 million, is extracted from the "wilt-resistant 'Todd's Mitcham' cultivar, a product of thermal neutron irradiation." She adds that "the exact nature of the genetic changes that cause it to be wilt-resistant remain unknown."

But for some New Yorkers, a vegetable-filled rooftop is far more conceivable and practical than moving to the country. Novak agrees. "When these farmers go in and lecture these inner city kids about dairy farming in upstate New York, it's in one ear and out the other. But I can tell them, I have two farms in the city," and they can take the subway and come help on the weekends.

I'm told a rule of thumb for potato harvests is 10 pounds per pound of seed. I got 25 pounds for my one pound, so I guess I shouldn't be too disappointed about the results of my first year planting potatoes. Still it's nowhere near the 60 pound average that Greg Lutovsky's customer's experienced. In hindsight I think I got lazy in hilling my potato plants as they were growing. Sometimes I would let them get to be 8 or so inches tall and jungle-like before dumping more dirt in and covering the stems.